Zhang Xiao, Ye Fangwei, Kartashov Yaroslav V, Chen Xianfeng
Opt Express. 2015 Mar 9;23(5):6731-7. doi: 10.1364/OE.23.006731.
We study stimulated mode conversion and dynamics of Rabi-like oscillations of weights of guided modes in deeply subwavelength guiding structures, whose dielectric permittivity changes periodically in the direction of light propagation. We show that despite strong localization of the fields of eigenmodes on the scales below the wavelength of light, even weak longitudinal modulation couples modes of selected parity and causes periodic energy exchange between them, thereby opening the way for controllable transformation of the internal structure of subwavelength beams. The effect is reminiscent of Rabi oscillations in multilevel quantum systems subjected to the action of periodic external fields. By using rigorous numerical solution of the full set of the Maxwell's equations, we show that the effect takes place not only in purely dielectric, but also in metallic-dielectric structures, despite the energy dissipation inherent to the plasmonic waveguides. The stimulated conversion of subwavelength light modes is possible in both linear and nonlinear regimes.
我们研究了在深度亚波长波导结构中受激模式转换以及导模权重的类拉比振荡动力学，该结构的介电常数在光传播方向上呈周期性变化。我们表明，尽管本征模的场在低于光波长的尺度上有很强的局域化，但即使是微弱的纵向调制也会耦合选定奇偶性的模式，并导致它们之间的周期性能量交换，从而为亚波长光束内部结构的可控变换开辟了道路。这种效应让人联想到受周期性外部场作用的多能级量子系统中的拉比振荡。通过对麦克斯韦方程组的完整集合进行严格的数值求解，我们表明这种效应不仅发生在纯介质结构中，也发生在金属 - 介质结构中，尽管等离子体波导存在能量耗散。亚波长光模式的受激转换在线性和非线性区域都是可能的。
